The invention relates to a separating wheel for an air separator with separator wheel blades with blade ends lying radially to the outside which are tilted backwards in the direction of rotation of the separating wheel.
In practice, separating wheels with radially aligned blades are most common. For powder qualities with a maximum grain of roughly 100 microns satisfactory results are also possible with them.
When powder qualities with a maximum grain of roughly 60 microns are to be achieved, it is more advantageous to use separating wheels with blades tilted backward. Separating wheels with blades which are tilted against the direction of rotation of the separating wheel are known for example from DD 246 049 A1. The separation behavior, i.e. exact separation between the coarse and fine grain, is thus generally better, the more radically the blades are tilted. i.e. the larger the angle between the blades and the radial direction. Here the problem arises that the angle of incline is limited at roughly 35xc2x0 since for greater inclines the separated material can attach to the rear wall of the separating wheel blade, since the sliding angle is too little and the separated material is no longer conveyed away by the flow and causes operating problems.
Therefore the object of the invention is to make available a generic separating wheel in which separation behavior as good as possible is achieved by the blade ends titled backward and the resulting danger of deposits of separated material on the rear wall of the separating wheel blades is however avoided as much as possible. This object is achieved with a separating wheel with the features of claim 1.
With the separating wheel of the invention the two desired effects are advantageously achieved. First of all, the highly tilted front wall of the separating wheel blade yields very good separating behavior, since due to the radical incline of the front blade wall and the resulting higher centrifugal forces it is more difficult for the larger and heavier particles to enter the channel between the blades of the separating wheel. The smaller tilt of the rear wall of the separating wheel blade with respect to the radial furthermore prevents the separated material from attaching to the rear wall of the separating wheel blade. In this way very radical inclines of the blade ends become possible and they are beneficial for powder qualities with a maximum grain of less than 30 microns.
The respective angle of the front and rear wall of the separating wheel blades depends on many influencing factors, such as the rpm of the separating wheel, the type and composition of the separated material, and the desired degree of separation. But generally good separation behavior is achieved when the front blade wall is tilted at an angle greater than roughly 45xc2x0 and the rear blade wall is tilted at an angle of less than roughly 45xc2x0.
Within the framework of the invention it is preferable if the front blade wall is tilted at an angle between 50xc2x0 and 80xc2x0, preferably between 60xc2x0 and 70xc2x0 to the radial direction, and if the rear blade wall is tilted at an angle between 30xc2x0 and 45xc2x0, preferably roughly 40xc2x0, to the radial direction.
At these angles, in a host of cases it will be possible to achieved very good separation behavior.
Other advantageous embodiments of the invention are the subject matter of the other dependent claims.